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254

PRACTICAL ORGANIC CHEMISTRY

PREPARATIONS 19—20.

Glycocoll.—By the action of primary and secondary amines,
corresponding amino-acids are formed. Chloracetic acid and
methylamine yield sarcosine,

xCl                                 /NHCI-L

CH2           + NH3CH8 = CH2            + HC1.

\COOH                       \COOII

The   amino-acids   are   further   obtained   by  the   reduction
(Zn and HC1) of nitro-, oximino- and cyano-acids, thus :
CHo(N().2).COOII + 3Ha= CHa(NI Ia)COOII + 2li2O,
CH3.C(NOli).COOH + 2llo = CH3.C1I(NH.,).COOII + HaO9
CN.COOH -h 2lL = CHo(NII.2).c6oH,

and by the action of NH3 on the cyanhydrin of aldehydes and
ketones, or simply of ammonium cyanide. The product is then
hydrolysed with HC1,

/CN

/         NH3

/CN

CH3.CH

H.,0

/COOII

HCN
CH3.COH •>    CII3.CII

\>H              \Nl-Ia           \NII,

The amino-acids are crystalline compounds usually of a sweet
taste and soluble in water. They are neutral compounds, from
which it may be assumed that an inner ammonium salt is
formed—

/NH3

Nboo

By the action of an acid chloride on the amino-acid, the hydro-
gen of the amino-group may be replaced by an acicl  radical.
Hippuric acid has been synthesised in this way.
yNHo                            ,NH.CO.CGH5

CH2         + C6H5COC1 = Clio                 + IIC1   .

\coon                   XCOOH

The amino-acids are not acted on by a hot solution of caustic
alkali, but on fusion with caustic soda or potash, yield the
amine and CO,,,

/NH2

CH,.CH            - CIL.CH2.NH2

\COOH

CO2.